Derivatives - Pre-tax Effects of Derivatives Designated as Cash Flow Hedging Instruments (Details) (Energy Related Derivative [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2014		Dec. 31, 2013
Southern Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	$ (41)		$ (32)
Alabama Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(6)		(1)
Georgia Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(11)		(16)
Gulf Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(16)		(10)
Mississippi Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(8)		(5)
Other regulatory assets current [Member] | Southern Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(27)		(26)
Other regulatory assets current [Member] | Alabama Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(5)		(3)
Other regulatory assets current [Member] | Georgia Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(10)		(13)
Other regulatory assets current [Member] | Gulf Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(7)		(6)
Other regulatory assets current [Member] | Mississippi Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(5)		(4)
Other regulatory assets deferred [Member] | Southern Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(25)		(29)
Other regulatory assets deferred [Member] | Alabama Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(6)		(5)
Other regulatory assets deferred [Member] | Georgia Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(2)		(8)
Other regulatory assets deferred [Member] | Gulf Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(12)		(11)
Other regulatory assets deferred [Member] | Mississippi Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(5)		(6)
Other regulatory liabilities current [Member] | Southern Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	9		16
Other regulatory liabilities current [Member] | Alabama Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	4		5
Other regulatory liabilities current [Member] | Georgia Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	1		3
Other regulatory liabilities current [Member] | Gulf Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	2		5
Other regulatory liabilities current [Member] | Mississippi Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	2		3
Other regulatory liabilities deferred [Member] | Southern Company [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	2	[1]	7	[2]
Other regulatory liabilities deferred [Member] | Alabama Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	1	[1]	2	[2]
Other regulatory liabilities deferred [Member] | Georgia Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	0	[1]	2	[2]
Other regulatory liabilities deferred [Member] | Gulf Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	1	[1]	2	[2]
Other regulatory liabilities deferred [Member] | Mississippi Power [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	$ 0	[1]	$ 2	[2]

[1] Georgia Power includes other regulatory liabilities, deferred in other deferred credits and liabilities.Regulatory Hedge Unrealized Gain (Loss) Recognized on the Balance Sheet at December 31, 2013Derivative Category and Balance SheetLocation SouthernCompany AlabamaPower GeorgiaPower GulfPower MississippiPower (in millions)Energy-related derivatives: Other regulatory assets, current $(26) $(3) $(13) $(6) $(4)Other regulatory assets, deferred (29) (5) (8) (11) (6)Other regulatory liabilities, current 16 5 3 5 3Other regulatory liabilities, deferred (a) 7 2 2 2 2Total energy-related derivative gains (losses) $(32) $(1) $(16) $(10) $(5)

[2] Georgia Power includes other regulatory liabilities, deferred in other deferred credits and liabilities.